Means for cooling piercing points of tube rolling mills



J. w. KELSO 2,261,937

MEANS FOR COOLING PIERCING POINTS OF TUBE ROLLING MILLS Nov. 11, 1941.

Filed July 22, 1939 m Q Q 5 7 Q M? f 4 1i- EEE f N W I MN! i i M WI H 11. hi 0 V ////A/ 9% 3 fi J Q. .Q mm w m ME ?V// K & N\ I .F N\ f w w m h Patented Nov. 11, 1941 MEANS FOR COOLING PIERCING POINTS OF TUBE ROLLING MILLS John W. Kelso, East McKeesport, Pa., assignor to.

National Tube Compan Jersey y, a corporation of New Application July 22, 1939, Serial No. 286,016

3 Claims.

This invention relates to tube or pipe rolling mills and, particularly, to an improved means for cooling the piercing points thereof.

In one method of manufacturing pipes or tubes, as is well known to those skilled in the art, it is the practice after first piercing the hot steel billet to expand and shape the resulting shell to size by providing a mandrel bar having a larger piercing point on the end thereof and to expand the shell or cylindrical blank by forcing it over a piercing pointand mandrel bar, thereby expanding the shell which, of course, results in the shell surrounding and enclosing therein both the mandrel bar and the piercing point during the expanding operation. Consequently, the mandrel bar and piercing point become extremely hot and overheated after a short period of use and tend to become distorted, thereby rendering them unfit for further use. It is now'the general practice to cool the mandrel bars by making them hollow and supplying a cooling .fluid thereto to cool the same, thereby eliminating any danger of them becoming overheated and distorted. However, no provision has been made for cooling the piercing points, especially the outer surfaces thereof and dissipating the heat absorbed thereby from the hot steel shells or blanks.

Accordingly, it is one of the objects of the present invention to provide an improved means for cooling piercing points of tube or pipe rolling mills which is very effective in its operation and use, thereby completely dissipating the heat therefrom.

. It is another object of the present invention to provide an improved means for cooling piercing points of tube or pipe rolling mills which is simple and inexpensive in its construction, and, at the same time, one that is rugged and easily maintained.

Various other objects and advantages of this invention will become more apparent in the course of the following specification, and will be particularly pointed out in the appended claims.

In the accompanying drawing there is shown, for the purpose of illustration and description, one embodiment which my invention may assume in practice.

In the drawing:

Figure 1 is a horizontal longitudinal section through the improved means for cooling piercing points of my invention;

Figure 2 is a similar vertical section therethrough;

Figure 3 is a sectional view taken on the line III-III of Figure 1.

Referring more particularly to the drawing. there is shown a pair of driven metal-working rolls 2 and guides 3 of the conventional type for drawing a pierced shell or blank 4 over the piercing point 5 and hollow mandrel bar 6 to expand and elongate the same, a practice which is well known to those skilled in the art.

According to the present invention, there is disposed in the outer endof the mandrel bar 6 between the end thereof and. the piercing point 5, a bar cap member I having a reduced inner threaded end portion 8 which is screwed into the outer end of the mandrel bar. On the inner end of the bar cap 1 there is arranged an outwardly tapered or tang portion 9 having a relatively small outer diameter on which the piercing point 5 is disposed. The intermediate portion ll] of the bar cap 1 preferably has an outer diameter substantially equal to the outer diameter of the mandrel bar 6 and there is arranged axially through the bar cap I an opening or passageway 12. There is disposed axially in the inner end of the piercing point 5 an inwardly tapered opening l3 corresponding with the outwardly tapered or tang portion 9 of the bar cap 1 for holding the piercing point in position thereon. There is arranged axially in the outer or forward end of the piercingpoint 5, an opening M in which there is disposed a nozzle member Hi. In the piercing point 5 between the opening l3 in the inner end thereof and the opening M in the outer end thereof, there is arranged an inner chamber Hi. There is disposed within the mandrel bar 6 and extending through the opening l2 in the bar cap I and terminating in the chamber I6 of the piercing point 5 a cooling fluid supply pipe l'l having an outer diameter slightly smaller than the diameter of the axial opening l2 of the bar cap.

The nozzle member 15 disposed in the outer end of the piercing point 5 consists of a body portion 18 having a reduced threaded portion on the inner end thereof which is adapted to cooperate with an interiorly threaded portion in the outer end of the opening !4 so as to be securely held therein. The outer portion IQ of the body member. I 8 conforms substantially to the pointed portion or forward end of the piercing point and there is arranged therein a plurality of angularly, radially extending passageways or jets 20 which communicate with an axially arranged passageway 2| disposed in the body member It. There is preferably arranged on the inner end of the body member l8 a conical shaped screen or strainer member 22 which is preferably screwed into the outer end of the passageway 2| of the body member and preferably extends into, the chamber it of the piercing point. There is accurely arranged on the outer end of the body member l8 beyond the outer portion I! a caplike member 23.

It will be understood that the cooling fluid used, preferably water, is introduced under pressure from a source of supply into and through the hollow mandrel bar i and bar cap I into the inner chamber IS in the piercing point by means of the fluid supply pipe II. The cooling fluid then passes from the inner chamber I through the conical shaped screen or strainer 22 in the inner end of the nozzle I5, which separates any foreign materials from the cooling fluid, into and through the passageway 2| and out through the radially extending passageways or jets 2|! which deliver the cooling fluid forcibly therefrom against the inner walls of the cap member 23 which, in turn, directs a circular spray forms may be devised within the scope of my invention, as deflned in the appended claims.

I claim:

1. In a tube rolling mill, a hollow mandrel bar, a hollow mandrel plug arranged on the outer end of said mandrel bar, means for supplying a cooling fluid into and through said mandrel bar into the hollow interior of said plug, a nozzle member arranged on the extreme outer end of said plug communicating with the hollow interior thereof, said nozzle member having a main fluid passageway therein arranged substantially axially thereof and a plurality of radially extending fluid pasof the cooling fluid back over the piercing point 1 to cool the same. It will be seen that, if an excessive amount of the cooling fluid were delivered to the inner chamber it, it would overflow and pass back through the opening I2 in the bar cap I on/the outside of the cooling fluid supply pipe 11 into the mandrel bar 6, thereby tending to dissipate any heat absorbed by the bar cap I as 'well as by the mandrel bar 6. It will be noted also that, due to the shell assuming an oval sectional conformation in the working zone, as shown in Figure 2 ofthe drawing, two cavities are formed, one at each side of the shell between the inner surface thereof and the piercing point, that is, there is always a clearance therebetween at the sides of the piercing point on which the guides 3 are disposed during the drawing operation, thereby permitting the cooling fluid to pass along the exterior surface of the piercing point at these points so as to reach practically the entire exterior surface of the same.

As a result of my invention. it will be seen that there is provided a cooling means which quickly and effectively dissipates; the heat absorbed by the piercing point from the hot steel shell thereby eliminating the danger of the piercing point becoming overheatd and damaged.

While the improved cooling means of my invention is shown incorporated with a piercing point for the purpose of cooling the same, it will be understood that my improved cooling means can be used in connection with any other typeof point or mandrel bar plug such as, for example,

- in connection with the type of plug used on rotary rolling mills for sizing and expanding pipe.

While I have shown and described one embodiment of my invention, it will be understood that this embodiment is merely for the purpose of illustration and description and that various other sageways communicating with said main fluid passageway, and means arranged with said noz zle member beyond said radially extending fluid passageways whereby said cooling fluid as it is delivered through and from said passageways is directed back over the exterior surface of the mandrel plug in substantially a circular spray.

2. In a tube rolling mill, a hollow mandrel bar, a hollow mandrel plug arranged on the outer end of said mandrel bar, means for supplying a cooling fluid into and through said mandrel bar into the hollow interior of said plug, a nozzle member arranged on the extreme outer end of said plug communicating with the hollow interior thereof, said nozzle member having a main fluid passageway therein arranged substantially axially thereof and a plurality of radially extending fluid passageways communicating with said main fluid passageway, and a cap member arranged with said nozzle member beyond said radially extending fluid passageways, said cooling fluid adapted to be delivered through said passageways and against the interior walls of said cap member whereby it is directed thereby back over the exterior surface of the mandrel plug in substantially a circular spray.

3. In a tube rolling mill, a. hollow mandrel bar, a. bar cap arranged on the outer end of said mandrel bar, a mandrel plug having an inner chamber therein arranged on the outer end of said bar cap, means for supplying a cooling fluid into and through said mandrel bar and said bar cap into the chamber in said piercing point, a nozzle member arranged on the extreme outer end of said plug, said nozzle member having a main fluid passageway therein arranged substantially axially thereof and communicatin with the chamber in said piercing point and a plurality of radially extending fluid passageways communicating with said main fluid-passageway, and means arranged with said nozzle member beyond said radially extending fluid passageways whereby said cooling fluid as it is delivered through and from said passageways is directed back over the exterior surface of the mandrel plug in substantially a circular spray.

JOHN W. KELSO. 

